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Sannigrahi J, Chattopadhyay S, Dutta D, Giri S, Majumdar S. Magnetic and electric properties of CaMn7O12 based multiferroic compounds: effect of electron doping. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:246001. [PMID: 23709515 DOI: 10.1088/0953-8984/25/24/246001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The mixed valent multiferroic compound CaMn7O12 is studied for its magnetic and electric properties. The compound undergoes magnetic ordering below 90 K with a helimagnetic structure followed by a low temperature magnetic anomaly observed around 43 K. This study shows that the magnetic anomaly at 43 K is associated with thermal hysteresis indicating the first order nature of the transition. The compound also shows field-cooled magnetic memory and relaxation below 43 K, although no zero-field-cooled memory is present. A clear magnetic hysteresis loop is present in the magnetization versus field measurements, signifying the presence of some ferromagnetic clusters in the system. We doped trivalent La at the site of divalent Ca expecting to enhance the fraction of Mn(3+) ions. The La doped samples show reduced magnetization, although the temperatures associated with the magnetic anomalies remain almost unaltered. Interestingly, the spontaneous electrical polarization below 90 K increases drastically on La substitution. We propose that the ground states of the pure as well as the La doped compositions contain isolated superparamagnetic like clusters, which can give rise to metastability in the form of field-cooled memory and relaxation. The ground state is certainly not spin glass type, as is evident from the absence of zero-field-cooled memory and frequency shift in the ac susceptibility measurements.
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Das Roy L, Giri S, Singh S, Giri A. Effects of radiation and vitamin C treatment on metronidazole genotoxicity in mice. Mutat Res 2013; 753:65-71. [PMID: 23416157 DOI: 10.1016/j.mrgentox.2013.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 01/26/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
Abstract
The impact of exposure to low dose radiation (LDR) on human health is not clear. Besides, cross adaptation or sensitization with pharmaceutical agents may modify the risk of LDR. In the present study, we analyzed the interaction of radiation and metronidazole (MTZ) in inducing chromosome aberration (CA) and micronucleus (MN) in the bone marrow cells of Balb/C mice in vivo. Further, we evaluated the efficacy of vitamin C to reduce MTZ induced genotoxicity. We found that 10, 20 and 40mg/kg of MTZ induced dose dependent increase in the frequency of CA (r=0.9923, P<0.01) as well as MN (r=0.9823, P<0.05) in polychromatic erythrocytes. However, MTZ did not affect the ratio of polychromatic erythrocytes to normochromatic erythrocytes indicating lack of cytotoxicity. Supplementation with vitamin C prior to MTZ treatment significantly reduced the frequency of CA (P<0.001) as well as MN (P<0.001). Radiation (0.5Gy) exposure prior to MTZ treatment produced a less than additive (for CA) to additive (for MN) effects. However, radiation exposure following MTZ treatment produced additive (for CA) and synergistic (for MN) effects. Further, vitamin C pre-treatment also reduced the genotoxicity indices following the combined treatment of MTZ and radiation. Our findings suggest that MTZ may sensitize bone marrow cells to radiation exposure and enhances genotoxicity. We recommend more studies on the interaction of LDR and marketed pharmaceuticals to minimize possible harmful outcomes through appropriate precautionary measures.
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Yadav SS, Giri S, Singha U, Boro F, Giri A. Toxic and genotoxic effects of Roundup on tadpoles of the Indian skittering frog (Euflictis cyanophlyctis) in the presence and absence of predator stress. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 132-133:1-8. [PMID: 23454306 DOI: 10.1016/j.aquatox.2013.01.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 01/25/2013] [Accepted: 01/27/2013] [Indexed: 06/01/2023]
Abstract
Glyphosate, a post emergent herbicide, has become the backbone of no-till agriculture and is considered safe for animals. However, the impact of glyphosate on non-target organisms, especially on amphibians, is the subject of major concern and debate in recent times. We examined the toxic and genotoxic effects of Roundup, a commercial formulation of glyphosate, in the tadpoles of the Indian skittering frog (Euflictis cyanophlyctis). Roundup at different concentrations (0, 1, 2, 3, 4 and 8mg acid equivalent (ae)/L), tested in a 2×6 factorial design in the presence and absence of predator stress, induced concentration-dependent lethality in tadpoles. The 96-h LC50 for Roundup in the absence and presence of predator stress were 3.76mgae/L and 3.39mgae/L, respectively. The 10-day LC50 value for Roundup was significantly lower, 2.12mgae/L and 1.91mgae/L in the absence and presence of predator stress, respectively. Lower concentrations of Roundup (1, 2 and 3mgae/L) induced the formation of micronuclei (MN) in the erythrocytes of tadpoles at 24-h (F3,56=10.286, p<0.001), 48-h (F3,56=48.255, p<0.001), 72-h (F3,56=118.933, p<0.001) and 96-h (F3,56=85.414, p<0.001) in a concentration-dependent manner. Presence of predator stress apparently increased the toxicity and genotoxicity of Roundup; but these effects were not statistically significant. These findings suggest that Roundup at environmentally relevant concentrations has lethal and genotoxic impact on E. cyanophlyctis; which may have long-term fitness consequence to the species.
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Karmakar A, Majumdar S, Kundu S, Nath TK, Giri S. A Griffiths-like phase in antiferromagnetic R0.5Eu0.5MnO3 (R = Pr, Nd, Sm). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:066006. [PMID: 23315393 DOI: 10.1088/0953-8984/25/6/066006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We report a Griffiths-like phase in isovalent doped rare-earth manganites R(0.5)Eu(0.5)MnO(3) (R = Pr, Nd, Sm). Rietveld refinement of the structural data reveals strong orthorhombic and Jahn-Teller distortions. The dc and ac magnetic studies nicely demonstrate aspects of Griffiths phase-like behaviour. The presence of short range ferromagnetically correlated spin clusters is observed above the antiferromagnetic transition temperature. A disorder driven phase inhomogeneity arising from strong structural distortion is the possible origin of this behaviour.
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Edelman RR, Giri S, Dunkle E, Galizia M, Amin P, Koktzoglou I. Quiescent-inflow single-shot magnetic resonance angiography using a highly undersampled radial k-space trajectory. Magn Reson Med 2013; 70:1662-8. [PMID: 23348595 DOI: 10.1002/mrm.24596] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 11/01/2012] [Accepted: 11/26/2012] [Indexed: 11/09/2022]
Abstract
PURPOSE We hypothesized that high undersampling factors could be used in conjunction with radial quiescent-inflow single-shot magnetic resonance angiography (MRA) to accelerate the data acquisition and enable multislice acquisitions. METHODS Seven subjects were imaged on a 1.5 T MRI system. For multislice quiescent-inflow single-shot MRA, the venous saturation radiofrequency pulse, in-plane saturation radiofrequency pulse, and quiescent interval were applied only once before the first slice. RESULTS The mean (standard deviation) measurements for the intra-arterial signal-to-noise ratio were as follows: Cartesian 1 slice-29.3 (5.5); radial 1 slice, 92 views-22.3 (3.6); radial 1 slice, 46 views-18.5 (2.0); radial 2 slices, 46 views-18.3 (3.2); and radial 3 slices, 32 views-21.7 (3.9), normalized for pixel size to 15.8. Horizontal striping was present with multislice radial quiescent-inflow single-shot MRA (especially with the three-slice acquisition) due to variable T1 relaxation between the concurrently acquired slices, but the image quality remained diagnostic. Vascular pathology in patients with peripheral arterial disease was well shown by all techniques. CONCLUSION Very high undersampling factors in excess of 18 have been demonstrated for nonenhanced MRA using a radial quiescent-inflow single-shot technique, enabling the acquisition of two to three slices per cardiac cycle. Scan time for a complete peripheral MRA could be shortened to 2 min or less.
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Giri S, Kindo AJ. A review of Candida species causing blood stream infection. Indian J Med Microbiol 2013; 30:270-8. [PMID: 22885191 DOI: 10.4103/0255-0857.99484] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The incidence of candidemia has been on a rise worldwide. The epidemiology of invasive fungal infections in general and of candidemia in particular has changed in the past three decades because of a variety of factors like the AIDS epidemic, increased number of patients receiving immunosuppressive therapy for transplantation and the increasing use of antimicrobials in the hospital setups and even in the community. The important risk factors for candidemia include use of broad-spectrum antimicrobials, cancer chemotherapy, mucosal colonization by Candida species, indwelling vascular catheters like central venous catheters, etc. More than 90% of the invasive infections due to Candida species are attributed to five species-Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida krusei. However, the list of new species of Candida isolated from clinical specimens continues to grow every year. Early diagnosis and proper treatment is the key for management of candidemia cases.
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Mangalam A, Poisson L, Nemutlu E, Datta I, Denic A, Dzeja P, Rodriguez M, Rattan R, Giri S. Profile of Circulatory Metabolites in a Relapsing-remitting Animal Model of Multiple Sclerosis using Global Metabolomics. ACTA ACUST UNITED AC 2013; 4. [PMID: 24273690 DOI: 10.4172/2155-9899.1000150] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the CNS. Although, MS is well characterized in terms of the role played by immune cells, cytokines and CNS pathology, nothing is known about the metabolic alterations that occur during the disease process in circulation. Recently, metabolic aberrations have been defined in various disease processes either as contributing to the disease, as potential biomarkers, or as therapeutic targets. Thus in an attempt to define the metabolic alterations that may be associated with MS disease progression, we profiled the plasma metabolites at the chronic phase of disease utilizing relapsing remitting-experimental autoimmune encephalomyelitis (RR-EAE) model in SJL mice. At the chronic phase of the disease (day 45), untargeted global metabolomic profiling of plasma collected from EAE diseased SJL and healthy mice was performed, using a combination of high-throughput liquid-and-gas chromatography with mass spectrometry. A total of 282 metabolites were identified, with significant changes observed in 44 metabolites (32 up-regulated and 12 down-regulated), that mapped to lipid, amino acid, nucleotide and xenobiotic metabolism and distinguished EAE from healthy group (p<0.05, false discovery rate (FDR)<0.23). Mapping the differential metabolite signature to their respective biochemical pathways using the Kyoto Encyclopedia of Genes and Genomics (KEGG) database, we found six major pathways that were significantly altered (containing concerted alterations) or impacted (containing alteration in key junctions). These included bile acid biosynthesis, taurine metabolism, tryptophan and histidine metabolism, linoleic acid and D-arginine metabolism pathways. Overall, this study identified a 44 metabolite signature drawn from various metabolic pathways which correlated well with severity of the EAE disease, suggesting that these metabolic changes could be exploited as (1) biomarkers for EAE/MS progression and (2) to design new treatment paradigms where metabolic interventions could be combined with present and experimental therapeutics to achieve better treatment of MS.
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Chattopadhyay S, Jana S, Giri S, Majumdar S. An agglomeration induced glassy magnetic state in a carbon nanotube/NiO nanocomposite system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:436005. [PMID: 23041910 DOI: 10.1088/0953-8984/24/43/436005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A series of nanocomposite materials were synthesized using multi-walled carbon nanotubes (MWCNTs) and NiO nanoparticles by varying the concentration of NiO in the MWCNT host matrix. Such an increment in the NiO particle density actually tunes the degree of isolation among the magnetic nanoparticles. Careful investigation by transmission electron microscopy shows that particle agglomeration increases substantially with NiO particle density. Field dependence of magnetization measurements depict a gradual enhancement of coercivity with increasing NiO concentration, signifying the enhancement of magnetic anisotropy in this nanocomposite system. Furthermore, field cooled and zero field cooled memory effect as well as magnetization relaxation measurements show that a glassy magnetic state gradually develops when the concentration increases. Analysis based on the result of high resolution transmission electron microscopy along with the magnetization data reveals that interparticle magnetic exchange interaction in the presence of interfacial disorders plays the major role in the emergence of the glassy magnetic state in this nanocomposite system.
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Chatterjee S, Giri S, Majumdar S. Metastability and inverse magnetocaloric effect in doped manganite (Nd(0.25)Sm(0.25)Sr(0.5)MnO3) and ferromagnetic shape memory alloy (Ni2Mn(1.36)Sn(0.64)): a comparison. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:366001. [PMID: 22892947 DOI: 10.1088/0953-8984/24/36/366001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The manganite Nd(0.25)Sm(0.25)Sr(0.5)MnO(3) (NSSMO) shows a first-order metal to insulator transition on cooling, which is concomitant with a magnetic transition from the ferromagnetic to antiferromagnetic state. In some respect the sample shows a striking similarity with Ni-Mn-Sn based ferromagnetic shape memory alloys (FSMAs) undergoing a first-order magneto-structural transition, and efforts have been made to highlight the similarities and dissimilarities of the studied manganite with one such FSMA of composition Ni(2)Mn(1.36)Sn(0.64). From our transport and magnetic investigations, the region of transition in the NSSMO is found to be highly metastable, with a clear indication of a magnetically arrested state which persists even when the sample is cooled down to the lowest temperature of measurement. Interestingly, the studied manganite shows an inverse magnetocaloric effect similar to the FSMA. However, a striking difference between the two compositions is evident in the low-temperature magneto-transport behavior: while a clear signature of tunneling magnetoresistance is present in NSSMO due to the coexisting metallic and insulating clusters of nanometer dimension, the studied FSMA do not show such behavior due to the absence of any insulating phase in the intermetallic alloy.
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Giri S, Sharma SR, Timalsina S, Yadav V, Koirala S, Kumar A, Neupane S, Neupane M. Cardiovascular health risk behavior among medical students in a teaching hospital. JOURNAL OF NEPAL HEALTH RESEARCH COUNCIL 2012; 10:187-191. [PMID: 23281448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
BACKGROUND Medical students are the health care providers of tomorrow. The health behaviors that are acquired in early life and in medical school will influence their future acceptance and practice of preventive strategies including their interaction with patients. The main objective of our study was to assess the health behavior and perceptions of medical students in relation to cardiovascular diseases. METHODS A cross sectional descriptive study was done among 159 medical students of Institute of Medicine, Tribhuvan University Teaching Hospital in Kathmandu, Nepal from September 2010 to December 2010. Data collection was done using a self administered questionnaire. RESULTS The mean age was 22.9±2.5 yrs and a male:female ratio of 2.1:1. Thirty Five (22%) were current smokers, 56 (35%) indulged in episodic heavy drinking, 25 (15.7%) were overweight, 34 (21%) engaged in recommended amount of physical activitiy,58 (33%) regulated fat consumption and 46 (28%) regulated salt consumption. Regarding developing cardiovascular disease in the future, 85(53%) showed concern but only 33 (38%) of these adopted preventive practices. 101 (64%) believed that their medical school life had a harmful effect on their health. CONCLUSIONS Our study shows a high prevalence of cardiovascular risk behaviours among the medical students. This highlights the urgency that we must take to promote preventive knowledge and practices among medical students. This will help them to become prevention oriented clinicians in future to counter the increasing burden of cardiovascular diseases in this part of the world.
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Roymahapatra G, M. Mandal S, F. Porto W, Samanta T, Giri S, Dinda J, L. Franco O, K. Chattaraj P. Pyrazine Functionalized Ag(I) and Au(I)-NHC Complexes are Potential Antibacterial Agents. Curr Med Chem 2012; 19:4184-93. [DOI: 10.2174/092986712802430090] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 11/22/2022]
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Nandi UN, Sircar S, Karmakar A, Giri S. Nonlinearity exponent of ac conductivity in disordered systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:265601. [PMID: 22653102 DOI: 10.1088/0953-8984/24/26/265601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We measured the real part of ac conductance Σ(x,f) or Σ(T,f) of iron-doped mixed-valent polycrystalline manganite oxides LaMn(1-x)Fe(x)O(3) as a function of frequency f by varying initial conductance Σ(0) by quenched disorder x at a fixed temperature T (room) and by temperature T at a fixed quenched disorder x. At a fixed temperature T, Σ(x,f) of a sample with fixed x remains almost constant at its zero-frequency dc value Σ(0) at lower frequency. With increase in f, Σ(x,f) increases slowly from Σ(0) and finally increases rapidly following a power law with an exponent s at high frequency. Scaled appropriately, the data for Σ(T,f) and Σ(x,f) fall on the same universal curve, indicating the existence of a general scaling formalism for the ac conductivity in disordered systems. The characteristic frequency f(c) at which Σ(x,f) or Σ(T,f) increases for the first time from Σ(0) scales with initial conductance Σ(0) as f(c) ~ Σ(0)(x(f)), where x(f) is the onset exponent. The value of x(f) is nearly equal to one and is found to be independent of x and T. Further, an inverse relationship between x(f) and s provides a self-consistency check of the systematic description of Σ(x,f) or Σ(T,f). This apparent universal value of x(f) is discussed within the framework of existing theoretical models and scaling theories. The relevance to other similar disordered systems is also highlighted.
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Agarwal MP, Giri S, Gandhi V, Sharma A, Gupta R, Sharma V. Education and Imaging. Gastrointestinal: A cutaneous clue to painless acute on chronic pancreatitis. J Gastroenterol Hepatol 2012; 27:842. [PMID: 22436060 DOI: 10.1111/j.1440-1746.2012.07091.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
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Karmakar A, Majumdar S, Kundu S, Nath TK, Giri S. Observation of Griffiths phase in antiferromagnetic La(0.32)Eu(0.68)MnO3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:126003. [PMID: 22370010 DOI: 10.1088/0953-8984/24/12/126003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report the Griffiths phase (GP) scenario for isovalent doping in antiferromagnetic La(0.32)Eu(0.68)MnO(3). Rietveld refinement of structural data displays strong crystal structural distortion. The dc and ac magnetic studies nicely demonstrate unambiguous aspects of robust GP. The presence of ferromagnetically correlated spin clusters is found above the transition temperature, T(N). The disorder-driven phase inhomogeneity is correlated to strong structural distortion, giving rise to the GP. This is an unique example in manganite where double exchange interaction does not play any role for the observed phenomenon.
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Giri A, Yadav SS, Giri S, Sharma GD. Effect of predator stress and malathion on tadpoles of Indian skittering frog. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 106-107:157-163. [PMID: 22172542 DOI: 10.1016/j.aquatox.2011.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 05/31/2023]
Abstract
The impact of pesticides on amphibians is of particular concern because their populations appear to be declining on a global scale. We examined the toxic and genotoxic effects of malathion, a commonly used organophosphorus pesticide, in the larvae of Indian skittering frog (Euflictis cyanophlyctis). The different concentrations of malathion (0, 0.5, 1.0, 2.0, 4.0 and 8.0mg/L) tested in a 2×6 factorial design, induced concentration-dependent lethality in tadpoles in the presence and absence of predator cues. The 96 h LC50 for malathion in the presence and absence of predator stress were 3.523 mg/L and 3.588 mg/L, respectively. The 15-day LC50 value for malathion was estimated to be 2.452 mg/L. Lower concentrations of malathion extending into the sublethal range (0.5, 1.0 and 2.0 mg/L) induced micronuclei (MN) in the erythrocytes of tadpoles at 24 h (F₃,₅₆=70.291, p<0.001), 48 h (F₃,₅₆=78.423, p<0.001), 72 h (F₃,₅₆=88.817, p<0.001) and 96 h (F₃,₅₆=64.770, p<0.001) in a concentration-dependent manner. Predator stress significantly enhanced the MN frequency at 48 h following 1.0mg/L malathion treatment (p<0.001). The present report is the first one to analyze genotoxic effect of malathion in the presence of predator stress. These results suggest that predator stress may potentiate the genotoxic effect of lower concentrations of malathion in E. cyanophlyctis tadpoles. These effects may have long-term fitness consequence to the population as a whole.
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Srinivasu K, Ghosh SK, Das R, Giri S, Chattaraj PK. Theoretical investigation of hydrogen adsorption in all-metal aromatic clusters. RSC Adv 2012. [DOI: 10.1039/c2ra00643j] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Gurav SD, Gilibili RR, Jeniffer S, Mohd Z, Giri S, Govindarajan R, Srinivas NR, Mullangi R. Pharmacokinetics, tissue distribution and identification of putative metabolites of JI-101 - a novel triple kinase inhibitor in rats. ARZNEIMITTEL-FORSCHUNG 2012; 62:27-34. [PMID: 22331760 DOI: 10.1055/s-0031-1295427] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
JI-101, chemically 1-[1-(2-amino-pyridin-4-ylmethyl)-1H-indol-4-yl]-3-(5-bromo-2-methoxy-phenyl)-urea hydrochloride, is a novel orally active kinase inhibitor, which has shown potent in vitro and in vivo anticancer activity against a variety of cancer cell lines and xenografts. It is currently entering Phase II clinical development for the treatment of solid tumors. The aim of the study is to assess the metabolic stability of JI-101 in various pre-clinical and human liver microsomes, to identify the major CYPs (cytochrome β450) involved in the metabolism of JI-101 and identification of putative metabolites. We have also studied the pharmacokinetics, tissue distribution and excretion of JI-101 in Sprague Dawley rats. JI-101 was found to be stable in various liver microsomes tested. JI-101 is highly permeable and not a substrate for P-gp (permeability glycoprotein). JI-101 excreted through bile along with its mono- and di-hydroxy metabolites. Following oral administration, JI-101 was rapidly absorbed, reaching Cmax within 2 h. The t½ of JI-101 with intravenous and oral route was found to be 1.75 ± 0.79 and 2.66 ± 0.13 h, respectively. The Cl and Vd by intravenous route for JI-101 were found to be 13.0 ± 2.62 mL/min/kg and 2.11 ± 1.42 L/kg, respectively. The tissue distribution of JI-101 was extensive with rapid and preferred uptake into lung tissue. Overall, the oral bioavailability of JI-101 is 55% and the primary route of elimination for JI-101 is feces.
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Karmakar A, Majumdar S, Giri S. Tuning A-site ionic size in R(0.5)Ca(0.5)MnO3 (R = Pr, Nd and Sm): robust modulation in dc and ac transport behavior. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:495902. [PMID: 22121195 DOI: 10.1088/0953-8984/23/49/495902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Structural investigations on Pr(0.5)Ca(0.5)MnO(3), Nd(0.5)Ca(0.5)MnO(3) and Sm(0.5)Ca(0.5)MnO(3) display a systematic tuning in orthorhombic distortion which appears due to a change in A-site ionic size. Comprehensive investigations on dc conduction using various models indicate strong correlation with structural changes. Careful analysis of the ac conductivity mechanism as a function of frequency and temperature brings out a pronounced effect of structural modifications on the polaron conduction mechanism. Contrary to typical manifestations, dc conductivity and relaxation of charge carriers reveal non-Arrhenius behavior. This work provides a detailed and systematic addition to the phase diagram of electronic transport in the rare-earth manganite system doped with a divalent alkali atom.
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Bonassi S, Coskun E, Ceppi M, Lando C, Bolognesi C, Burgaz S, Holland N, Kirsh-Volders M, Knasmueller S, Zeiger E, Carnesoltas D, Cavallo D, da Silva J, de Andrade VM, Demircigil GC, Odio AD, Donmez-Altuntas H, Gattas G, Giri A, Giri S, Gómez-Meda B, Gómez-Arroyo S, Hadjidekova V, Haveric A, Kamboj M, Kurteshi K, Martino-Roth MG, Montoya RM, Nersesyan A, Pastor-Benito S, Salvadori DMF, Shaposhnikova A, Stopper H, Thomas P, Torres-Bugarín O, Yadav AS, González GZ, Fenech M. The HUman MicroNucleus project on eXfoLiated buccal cells (HUMNXL): The role of life-style, host factors, occupational exposures, health status, and assay protocol. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2011; 728:88-97. [DOI: 10.1016/j.mrrev.2011.06.005] [Citation(s) in RCA: 242] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/30/2011] [Indexed: 11/30/2022]
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Paudel PK, Giri S, Shrestha PS, Shrestha L, Thapa SB, Shrestha M. A case of precocious puberty in a setting with limited resources. Kathmandu Univ Med J (KUMJ) 2011; 9:315-317. [PMID: 22710547 DOI: 10.3126/kumj.v9i4.6353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Precocious puberty is a rare condition characterized by the development of secondary sexual characteristics before the median age for the sex. It is either gonadotropin dependent also called as central or gonadotropin independent also known as peripheral type. Hypothalamamic Hamartoma is a common cause of the central or precocious puberty due to organic brain lesion. Here we present a two year male who presented us with precocious puberty due to a hypothalamic Hamartoma.
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Giri A, Giri S, Sharma GD. Malathion and fenvalerate induce micronuclei in mouse bone marrow cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2011; 52:607-613. [PMID: 21538555 DOI: 10.1002/em.20649] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Revised: 01/25/2011] [Accepted: 01/25/2011] [Indexed: 05/30/2023]
Abstract
Health effects of pesticides are a major public health concern. In this study, the genotoxic effects of two commonly-used pesticides, malathion, and fenvalerate, were investigated in mice in vivo. Induction of micronuclei in bone marrow cells was used as the test parameter following exposure to 2.5, 5 or 10 mg/kg malathion by intraperitoneal (i.p.) or per oral (p.o.) exposure. Exposure by both routes was found to cause a significant increase in micronucleated polychromatic erythrocytes (PCEs) in a dose-dependent manner (r = 0.9769; P < 0.05). The highest dose (10 mg/kg) induced significant (P < 0.05) cytotoxicity. In contrast, fenvalerate caused an increase in micronucleated PCEs only at higher doses (10 and 20 mg/kg) via i.p. injection, and was not associated with cytotoxicity. A significant dose-response correlation was not observed in the dose ranges tested for fenvalerate (r = 0.8704; P > 0.05). The results suggest that technical grade malathion is a genotoxic agent. In contrast, technical grade fenvalerate appears to be a potent genotoxic agent, but this observation should be confirmed with further investigation(s).
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Das S, Majumdar S, Giri S. Multifunctional properties of CoNi alloy embedded in the SiO2 host: Role of interparticle interaction. J SOLID STATE CHEM 2011. [DOI: 10.1016/j.jssc.2011.06.038] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Agarwal MP, Giri S, Sharma V, Roy U, Gharsangi K. Dengue causing fulminant hepatitis in a hepatitis B virus carrier. Biosci Trends 2011; 5:44-5. [PMID: 21422600 DOI: 10.5582/bst.2011.v5.1.44] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Dengue is an acute febrile illness resulting from infection by a flavivirus transmitted by the Aedes mosquito. It is characterized by bleeding manifestations and a plasma leak syndrome. Hepatic involvement in the form of elevation in transaminases is common. However, acute hepatic failure is uncommon. It is not known how the presence of an underlying chronic hepatitis or liver disease affects the likelihood of severity of hepatitis from dengue. The present report is of a 33-year-old man, a carrier of hepatitis B virus, who presented with fever, altered sensorium, thrombocytopenia, and coagulopathy. He was diagnosed to have developed acute hepatic failure due to dengue. The patient improved with supportive measures.
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Rattan R, Giri S, Hartmann LC, Shridhar V. Metformin attenuates ovarian cancer cell growth in an AMP-kinase dispensable manner. J Cell Mol Med 2011; 15:166-78. [PMID: 19874425 PMCID: PMC3822503 DOI: 10.1111/j.1582-4934.2009.00954.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Metformin, the most widely used drug for type 2 diabetes activates 59 adenosine monophosphate (AMP)-activated protein kinase (AMPK), which regulates cellular energy metabolism. Here, we report that ovarian cell lines VOSE, A2780, CP70, C200, OV202, OVCAR3, SKOV3ip, PE01 and PE04 predominantly express -α1, -β1, -γ1 and -γ2 isoforms of AMPK subunits. Our studies show that metformin treatment (1) significantly inhibited proliferation of diverse chemo-responsive and -resistant ovarian cancer cell lines (A2780, CP70, C200, OV202, OVCAR3, SKVO3ip, PE01 and PE04), (2) caused cell cycle arrest accompanied by decreased cyclin D1 and increased p21 protein expression, (3) activated AMPK in various ovarian cancer cell lines as evident from increased phosphorylation of AMPKα and its downstream substrate; acetyl co-carboxylase (ACC) and enhanced β-oxidation of fatty acid and (4) attenuated mTOR-S6RP phosphorylation, inhibited protein translational and lipid biosynthetic pathways, thus implicating metformin as a growth inhibitor of ovarian cancer cells. We also show that metformin-mediated effect on AMPK is dependent on liver kinase B1 (LKB1) as it failed to activate AMPK-ACC pathway and cell cycle arrest in LKB1 null mouse embryo fibroblasts (mefs). This observation was further supported by using siRNA approach to down-regulate LKB1 in ovarian cancer cells. In contrast, met formin inhibited cell proliferation in both wild-type and AMPKα1/2 null mefs as well as in AMPK silenced ovarian cancer cells. Collectively, these results provide evidence on the role of metformin as an anti-proliferative therapeutic that can act through both AMPK-dependent as well as AMPK-independent pathways.
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Chattopadhyay S, Giri S, Majumdar S. Broken chain effect in doped SrCuO2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:216006. [PMID: 21558609 DOI: 10.1088/0953-8984/23/21/216006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the effect of magnetic (Ni) and nonmagnetic (Zn, Ga) doping on the overall magnetic behaviour of the spin chain compound SrCuO(2). The doping causes systematic reduction in the intrachain exchange interaction, and the influence is found to be almost independent of the dopant. The low temperature Curie tail in the temperature dependence of susceptibility also increases with the doping concentration, which is an indication of the enhanced chain breaking effect with doping. The doping also gives rise to nonlinearity in the isothermal magnetization behaviour, which can be accounted for by the effect of free/quasi-free spin in the doped sample. Our analysis indicates that doped Ni(2+) ions remain in a low spin state (S = 0) and behave almost similar to the nonmagnetic counterpart as far as the doping effects are concerned.
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